增加多个项目的数量和总价的jQuery

// HTML结构
<div id="project-list">
  <div class="project">
    <span class="name">项目1</span>
    <span class="price">100</span>
  </div>
  <div class="project">
    <span class="name">项目2</span>
    <span class="price">200</span>
  </div>
</div>

<button id="add-project">添加项目</button>
<button id="calculate-total">计算总价</button>
<span id="total-price">总价：0</span>

// JavaScript代码
$(document).ready(function() {
  var totalPrice = 0;

  // 添加项目
  $('#add-project').click(function() {
    var projectName = prompt('请输入项目名称：');
    var projectPrice = parseFloat(prompt('请输入项目价格：'));

    if (projectName && !isNaN(projectPrice)) {
      var project = $('<div class="project"></div>');
      var name = $('<span class="name"></span>').text(projectName);
      var price = $('<span class="price"></span>').text(projectPrice);

      project.append(name);
      project.append(price);
      $('#project-list').append(project);
    }
  });

  // 计算总价
  $('#calculate-total').click(function() {
    totalPrice = 0;

    $('.project .price').each(function() {
      totalPrice += parseFloat($(this).text());
    });

    $('#total-price').text('总价：' + totalPrice);
  });
});